Alright so, I have kinda a silly question. I'm making muffins and my oven can't fit a 12-count muffin tin so I'm going to have to use a 6-count muffin tin. No biggie, I can adjust the recipe and cook time but my question is how long can I keep the remaining muffin batter on the counter while the first batch is cooking?

Reason I'm asking is cause the recipe I'm following says to preheat at 425°F, then bake for 5 minutes at 425 before going down to 350°F for another 25-30 minutes. If I bake one batch would I need to wait for the oven to cool completely and then redo the whole preheating and baking process for the second batch? And will the muffin batter be alright just sitting there for the hour or so the first batch is baking/oven is cooling?